Which one of the following molecular hydrides acts as a Lewis acid?

1. NH₃         

2. H₂O         

3. B₂H₆           

4. CH₄

Which of the following molecules acts as a Lewis acid ?

1. (CH₃)₃B

2. (CH₃)₂O

3. (CH₃)₃P

4. (CH₃)₃N

The ionisation constant of ammonium hydroxide is 1.77 x 10^-5 at 298 K. Hydrolysis constant of ammonium chloride is

1. 5.65 x 10^-10

2. 6.50 x 10^-12

3. 5.65 x 10^-13

4. 5.65 x 10^-12

The oxide that is not expected to react with sodium hydroxide is : 

1. B₂O₃           

2. CaO

3. SiO₂             

4. BeO

The dissociation constants for acetic acid and HCN at 25$°$C are 1.5 xl0^-5 and 4.5 xl0^-10,

respectively. The equilibrium constant for the equilibrium,

CN^- + CH₃COOH  =    HCN + CH₃COO^-   would be

1. 3.0 x 10⁵

2. 3.0 x 10^-5

3. 3.0x10^-4

4. 3.0 x 10⁴

Equal volumes of three acid solutions of pH 3, 4 and 5 are mixed in a vessel. What will be

the H⁺ ion concentration in the mixture?

1. 1.11 x 10^-4 M             

2. 3.7 x 10^-4 M

3. 3.7 x 10^-3  M             

4. 1.11 x 10^-3 M

The value of equilibrium constant of the reaction HI (g) $\rightleftharpoons$ $\frac{1}{2}$ H₂(g) + $\frac{1}{2}$ I₂(g) is 8.0. The equilibrium constant of the reaction

H₂(g) + I₂(g) $\rightleftharpoons$2HI(g) will be

$$\begin{gathered} 1. \frac{1}{16} \\ 2. \frac{1}{64} \\ 3. 16 \\ 4. \frac{1}{8} \end{gathered}$$

Which one of the following ionic species has the greatest proton affinity to form stable compound?

(1) HS^-                         

(2) ${\mathrm{NH}}_2^{-}$

(3) F^-                           

(4) I^-

For the reaction,

 CH₄(g) + 2O₂(g) $\rightleftharpoons$CO₂(g) + 2H₂O (l),

 $∆$_rH = -170.kJ mol-1

Which of the following statements is not true?

(a) At equilibrium, the concentrations of CO₂(g) and H₂O(l) are not equal

(b) The equilibrium constant for the reaction is given by K_p = [CO₂]/[CH₄][O₂]

(c) Addition of CH₄(g) or O₂ (g) at equilibrium will cause a shift to the right

(d) The reaction is exothermic

The hydrogen ion concentration of a 10^-8 M HCl aqueous solution at 298 K (K_w = 10^-14) is:

(1) 1.0×10^-6 M

(2) 1.0525 x 10^-7 M

(3) 9.525 x 10^-8 M

(4) 1.0×10^-8 M